New research observes tiny mirid bugs roaring at each other like lions!

While they can hardly be called “kings of the jungle”, Macrolophus pygmaeus and Macrolophus costalis, two common species of mirid bugs, do seem to roar like lions, according to a new study. Found across the world, in a wide variety of climates, these tiny insects are known to feed on smaller pests, such as whitefly and aphids. For the very first time, researchers have been able to record the sounds made by the bugs, which, quite surprisingly, are similar to the roars of big cats.

For the research, scientist Valerio Mazzoni and his team, at Italy-based Edmund Mach Foundation, studied these tiny insects, to great lengths, recording their calls using highly-specialized instruments. Although too weak to be heard by the unaided ear, the researchers managed to amplify the sounds with the help of a device, known as laser vibrometer, that captures the minute vibrations produced on the leaves, on which the insects reside. Speaking about the discovery, Mazzoni said:

When you listen to these sounds through headphones you’d think you were next to a tiger or lion… It must be a specific organ in the abdomen producing the roars.

During their examination, the scientists observed that, when two of the male insects were placed on the same leaf, they seemed to embark on a sort of rumbling contest. As in the case of big cats, these bugs appeared to resort to roaring, as a way of demonstrating their authority as well as attracting the opposite sex. The females of the species, however, don’t seem to make such sounds.

Interestingly, these growls are transmitted through vibrations of the surface, on which the insects perch, instead of the oscillation of air molecules. Furthermore, they contain audio frequencies ranging all the way from 1 hertz to nearly 750 hertz, a feature that helps them travel further without getting muffled. The team observed another fascinating feature, unique to these bugs. Unlike most insects that need to be stationary in order to produce sounds, the Macrolophus bugs seem to roar only while walking. How they make these sounds, however, remains a mystery. Caroline Fabre, an entomology expert at the University of Cambridge, explained:

Communication by vibration is widespread during insect interactions. It is likely that many new examples of vibrational communication will be discovered.

The study, entitled “Substrate-Borne Vibrational Signals in Mating Communication of Macrolophus Bugs”, was recently published in the Journal of Insect Behavior.